“Today’s picture is unacceptable for the level of our democracy,” Interior Minister Prokopis Pavlopoulos told reporters after a government meeting. “We will not tolerate these events. We will do what we must.”

The government denied reports it was planning to declare a state of emergency but Prime Minister Costas Karamanlis was due to meet the president and party political leaders to discuss the crisis on Tuesday.

Protests have erupted in more than 10 cities across the nation of 11 million people, including northern Thessaloniki and the tourist islands of Crete and Corfu. Greeks overseas protested in London and Berlin.

On Monday night, rioting youths took control of central Athens and set fire to the huge Christmas tree. More than 130 shops have already been destroyed in the capital, dashing retailers’ hopes that Christmas would compensate for Greece’s darkening economic outlook.

The shooting of Grigoropoulos kindled smouldering anger among Greek youths, resentful at a widening gap between rich and poor.

Two police officers have been charged over the shooting, one with murder and the other as an accomplice. Police said one officer fired three shots after their car was attacked by 30 youths

The officer described firing warning shots but witnesses have said he took aim at the boy. A coroner’s report on Monday said it was not possible to be sure.